Very minor hint
Look up after solving step 1 and getting the second upgrade.
The code for the Caesar Cipher is 7.
Turn on all the lights, it will reveal an elevator code to the roof.
Use the code you can spot from the roof (use the code from step 3 to access the roof) to open the large VAB door.
Use the code you can spot from the roof to open the large VAB door. You can use the code "0000" to get back to the ground floor.
Now with all upgrades, you can see the moon.
The code to the launch pad is the name of the space station.
The two refueling stations have pipes that need to be reconnected into a closed system.